1. Field of the Invention
This invention relates to a novel thiazolidine-2,4-dione compound, a method for the production thereof, and a medicine containing the compound for the cure of diabetic complications. More particularly, it relates to a novel thiazolidine-2,4-dione compound combining an aldose reductase inhibiting action and a blood sugar depressing action which are useful for the cure of various complicated diseases involving cataract, retinopathy, neurotic disorder(neuropathy), and renal disorder(nephropathy).
2. Description of the Prior Art
The complex abnormality of various metabolisms induced by the deficiency in the action of insulin has no negligible participation in the onset of cataract, retinopathy, neurotic disorder, and renal disorder complicated with diabetes. The polyol path occupies a large proportion to all the metabolic paths of interest and the participation of this particular path is thought to be very logical. This polyol path consists in effecting the metabolism of an aldose such as glucose or galactose into a ketose such as fructose via a polyol such as sorbitol or galactose, for example.
In the diabetic patients, this polyol path exists in an advanced state and the consequent cellular accumulation of sorbitol is regarded as a problem. The enzyme which catalyzes the conversion of aldose to polyol as the first step in the polyol path is called an aldose reductase. It is thought to constitute the velocity-controlling enzyme of this path. It has been reported that a measure to inhibit the action of this aldose reductate and decelerate the production and accumulation of sorbitol is effective in curing various complications of diabetes. Thus, efforts have been extensively devoted to the development of medicines which inhibit the action of aldose reductase.
Thiazolidine dione compounds of a certain sort have been heretofore known as a blood sugar depressant EP-A-0 332 331. It has not yet been known that these compounds are possessed of an action to inhibit an aldose reductase.
Though the aldose reductase inhibiting agents which have been heretofore known to the art indeed are capable of decelerating the production and accumulation of sorbitol, they are devoid of an action to correct the state of high blood sugar which is the basic cause for diabetic complications. Thus, they are prominently effective in curing cataract and neurotic disorder which are thought to bear heavily on the polyol path and yet fail to manifest any conspicuous effect in curing renal disorder and retinopathy whose causes defy unique elucidation. In the circumstances, therefore, an earnest desire has been expressed for the development of a medicine which combines the action of inhibiting an aldose reductase and the action of depressing blood sugar and manifests an extensive effect in the cure of various diabetic complications.
An object of this invention, therefore, is to provide a novel thiazolidine-2,4-dione compound, a method for the production thereof, and a medicine containing the compound and used for the cure of diabetic complications.
Another object of this invention is to provide a medicine which combines an aldose reductase inhibiting action and a blood sugar depressing action and manifests an extensive effect in the cure of various diabetic complications.